1. Field of the Invention
This invention relates to tie rods used in the errection of form walls for concrete construction. Specifically, tie rods space apart and secure two opposed form panels and are used in conjunction with rigid horizontal and vertical bracing attached to the form panels. After concrete has been poured and cured, the bracing and form panels are removed. Tie rods of the "snap tie" variety have their end portions twisted and broken off to allow for their extraction from the hardened concrete.
2. Description of the Prior Art
The prior art includes tie rods of various designs. U.S. Pat. No. 3,806,080 describes a form system utilizing cone flanges, form ties, and form locks. U.S. Pat. No. 4,027,847 describes a tie rod with an expandable element at one end for abutting engagement with the inner surfaces of a form wall. U.S. Pat. No. 3,901,061 describes a form construction using opposed panels, grouting cores, and tie rods. U.S. Pat. No. 3,841,600 describes a concrete form tie assembly utilizing anchor pins, wedges, spool like sleeve members, and a plurality of gripping teeth. U.S. Pat. No. 3,998,424 describes a tie rod with an expandable locking cone. U.S. Pat. No. 3,941,346 describes a tie rod assembly utilizing resilient sealing and spacing means.
As shown by the above cited U.S. patents, the securing of tie rods to one side of a form panel remains a labor intensive operation requiring at least two workers. One worker must be holding the tie rod in place while another worker secures the end of the rod from outside of the form.
Another drawback of conventional tie rods is the difficulty often encountered in removing portions of the form panel due to concrete seeping through the form panel apertures during the hardening of the concrete.